Cast3D does not have it's own rendering engine. So for 3D graphics rendering Cast3D currently is ported to popular 3D engines, Sandy3D and Papervision3D.

Cast3D has it own data file. It is an XML file, which contains information about 3D scene, abjects of a scene, materials, textures, lighting, sound, camera etc.. and motion. Those who are familiar with COLLADA format, may find some similarity of data types in both file formats, but Cast3D file is much thiner and contains only data it can process.

To make process of creation of 3D Flash animations with Cast3D easy, import C++ library was introduced. Which purpose is to generate Cast3D XML file from exposed functionality of library. There are also few import utilities built on top of Import library available now for download, like 3dsMax (.3ds) file import utility and geometry generation sample. COLLADA file import is coming soon.

No native rendering engine's 3D data loaders are involved in loading process. Cast3D populates all the scene and motion data directly into the engine and controls transient or frame by frame rendering.

Here is 'Flying Stealth' sample (Sandy3D rendering engine). Originally imported from .3ds file, this model has a 'plane' motion, camera view point motion and synchronized 3D sound, which balance moves from right to left along with plane. Click on 'plane' to start animation:

Use controls (while not animating):
Rotate: Left-Mouse-Drag, Pan: Ctrl+Left-Mouse-Drag,
Zoom In/Out: Shift+Left-Mouse-Drag, or Mouse-Wheel
For more samples see Demo page.

Using code for one of provided samples, update URL path of the .xc3 XML file to load.

Build and add resulting SWF file to a HTML page.

yeah, it's that simple.

Main object class is 'Cast3d' which takes as arguments a rendering engine's 3D scene holder and Camera objects. Then it loads file and populates 3D scene graph for both. There is a way to override or add properties and interactive handles for specific geometry objects and materials during the load time.
For example, if somebody wants to modify a color, texture and lighting attributes of a material, or add some interactivity to 3D object, so it responds to a mouse click and triggers other actions.